Silica-based glass, such as soda-lime-silica glass, is prevalent in the manufacture of glass containers and other articles. Molten glass used to make such articles is conventionally prepared by melting various glass-forming materials in a furnace or tank at elevated temperature. The resulting molten glass typically contains gaseous inclusions, e.g., “blisters,” “bubbles,” or “seeds,” which need to be removed. The process of removing gaseous inclusions from molten glass is referred to as “refining,” and conventionally involves continued heating of the molten glass at high temperatures and for long periods of time to allow the gaseous inclusions to gradually rise to the surface of the molten glass and escape. This process is undesirably slow and requires high-energy input to maintain the molten glass at a suitably high temperature.
The general object of the present disclosure is to provide a process and an apparatus for continuously refining molten glass, which can increase the rate at which gaseous inclusions are removed from molten glass and thereby increase the efficiency of the refining process.
The present disclosure embodies a number of aspects that can be implemented separately from or in combination with each other.
A process for refining molten glass, in accordance with one aspect of the disclosure, includes: (a) introducing a stream of molten glass into a controlled environment; (b) distributing the stream of molten glass over a flow surface; (c) collecting the stream of molten glass from a downstream end of the flow surface to form a body of molten glass having a free surface exposed to the controlled environment; and (d) removing a stream of refined molten glass from the controlled environment at a location below the free surface of the body of molten glass.
A refining chamber for refining molten glass, in accordance with one aspect of the disclosure, includes: an inlet for receiving a stream of molten glass; a distribution section for distributing the stream of molten glass over a flow surface; a reservoir section for collecting the stream of molten glass from the distribution section to form a body of molten glass; and an outlet located below a free surface of the body of molten glass for discharging a stream of refined molten glass from the refining chamber. The refining chamber may further include an evacuation system for creating a sub-atmospheric pressure environment within the refining chamber.